Fluid damper, particularly for movable pieces of furniture

ABSTRACT

A fluid damper for movable pieces of furniture comprises a cylinder ( 1 ) and a piston ( 3 ) than can be linearly displaced therein. The piston ( 3 ) is provided with interspaced ring disks ( 8, 9, 10, 11 ), which comprise, in part, through-openings ( 15 ) for the damping fluid and can, in part, be elastically bent or can be displaced.

[0001] The invention relates to a fluid damper, in particular for moving furniture parts, with a cylinder and a piston linearly displaceable therein which has at least one opening for a damping fluid provided in the cylinder, and at least one movable ring disk in the area of the opening(s).

[0002] Such fluid dampers are used in order in particular to damp out the closure motion of moving furniture parts such as furniture doors, shutters or drawers, in the rearmost closing area.

[0003] According to the known state of the art, the cylinder is preferably attached to the furniture body, for example a furniture side or a furniture base, and the furniture doors or the front panel of a drawer strikes the piston rod of the piston during closing. The damping results from the flow resistance of the damping fluid when the piston is displaced. A hydraulic fluid, for example an oil (silicone oil) is preferably used as damping fluid. However gases, in particular air, can also be used.

[0004] The object of the invention is to improve a fluid damper of the type mentioned at the outset such that its damping-out action is better matched to the speed of the moved furniture part.

[0005] The object according to the invention is achieved by arranging the at least one ring disk such that it at least partially covers the opening(s) during the damping stroke of the piston.

[0006] An embodiment of the invention provides that the ring disk(s) is or are elastically bendable during the damping stroke.

[0007] It is advantageously provided that the ring disks have different rigidities, which is achieved for example by the ring disks having different thicknesses or being made of different materials.

[0008] A further embodiment of the invention provides that the piston is fitted with a pin on which the ring disks are housed axially displaceable, springs being provided which, in the resting position of the piston, separate the ring disks from the piston and from one another.

[0009] Three or four elastically movable ring disks are preferably provided.

[0010] Upon insertion of the piston rod, the hydraulic fluid flows through the ring gaps between the ring disks and the cylinder wall and through the openings in the piston. Depending on the speed of the moved furniture part and thus of the piston, the elastically bendable ring disks are bent back as a result of the flow resistance or the springs between the ring disks are compressed.

[0011] The greater the flow resistance thus produced, the smaller the effective throughflow diameter of the openings as the front ring disk in each case partly or fully covers the openings of the rings located behind it. The speed of the piston decreases accordingly. If the piston slows, the flow resistance also becomes smaller and the ring disks move back into their starting position, as a result of which the effective diameter of the openings is enlarged.

[0012] Various embodiments of the invention will be explained below using the figures of the attached drawings. There are shown in:

[0013]FIG. 1 a longitudinal section through a fluid damper according to the invention,

[0014]FIG. 2 cut section A of FIG. 1

[0015]FIG. 3 cut section B of FIG. 1,

[0016]FIG. 4 a longitudinal section through a piston according to the invention,

[0017]FIG. 6 a longitudinal section in the area of the piston through a fluid damper according to a further embodiment of the invention in the return position during a damping at low speed,

[0018] FIGS. 7 to 8 longitudinal sections through the fluid damper according to FIGS. 5 and 6 in various damping stages,

[0019]FIG. 10 a longitudinal section through a fluid damper in the piston area during the return,

[0020]FIG. 11 a longitudinal section through a fluid damper in the area of the piston during the damping,

[0021]FIG. 13 a longitudinal section through a further embodiment of a fluid damper in the resting or return position,

[0022] FIGS. 11 to 16 a longitudinal section through an embodiment of a fluid damper according to FIG. 13 in various damping positions,

[0023]FIG. 17 a longitudinal section through a further embodiment of a fluid damper in the area of the piston in the resting and opening position,

[0024] FIGS. 18 to 21 longitudinal sections through a fluid damper according to FIG. 17 in different stages of damping,

[0025]FIG. 22a a top view of a piston,

[0026]FIG. 22b a top view of the flat ring disk,

[0027]FIGS. 22c to 22 e in each case a top view of a bendable ring disk,

[0028]FIG. 22f a top view of a piston guide,

[0029]FIG. 23 a longitudinal section through a further embodiment of a fluid damper in the area of the piston in the resting position,

[0030]FIGS. 24 and 25 longitudinal sections through a fluid damper according to FIG. 23 in various stages of damping,

[0031]FIG. 26 a longitudinal section through a further embodiment of a fluid damper during damping,

[0032]FIG. 27 a longitudinal section through a further embodiment of a fluid damper in the area of the piston in the resting position and

[0033]FIG. 28 a longitudinal section through a fluid damper in the area of the piston according to the embodiment according to FIG. 27 during damping.

[0034] The fluid damper according to the invention consists in customary manner of a cylinder 1 in the cylinder chamber 2 of which a piston 3 is displaceable. The piston 3 sits at the end of a piston rod 4 which projects through an end-wall 5 of the cylinder 1. A seal 6, which seals off the piston rod 4, is provided in the end-wall 5.

[0035] Housed on the piston rod 1, outside the cylinder in the embodiment according to FIG. 1, is a spring 7 which, after damping is completed, moves the piston rod 3 over the piston rod 4 and, in the case of opened furniture parts, back into the operating position. Spring 7 can also be arranged in the cylinder 1.

[0036] In the embodiment according to FIGS. 1 to 4, four elastically bendable ring disks 8, 9, 10, 11 are arranged at the front of the piston 3. The elastically bendable ring disks 8, 9, 10, 11 are made for example of a rubber or a plastics material. The piston 3 can likewise be made of plastic or else a metal.

[0037] There are ring gaps 14 between the elastically bendable ring disks 8, 9, 10, 11 and the cylinder wall 13.

[0038] Whereas the first ring disk 8 which is foremost relative to the direction of the damping movement has no opening, the second elastically bendable ring disk 9 is provided with a opening 15, the third elastically bendable ring disk 10 with two openings 15 and the fourth elastically bendable ring disk 11 with three openings 15. The piston 3 itself has six openings 15.

[0039] The ring disks 8, 9, 10, 11 have different thicknesses. During the damping movement, at a relatively high speed of the piston 3, the elastically bendable ring disks 8, 9, 10, 11 are bent back as shown by the dotted lines in FIG. 2 and cover the opening 15 or the openings 15 of the ring disks 9, 10, 11 located behind them in each case or of the piston 3. In this way, the throughflow volume of the hydraulic fluid decreases and the piston 3 is braked more sharply. At a higher advance speed of the piston 3, all the openings 15 of the piston 3 are covered. In the resting position, regardless of the position of the piston 3, the six openings 15 in the piston 3 are opened. They also remain opened when the piston 3 is again moved back into the ready position.

[0040] In the embodiment shown, at least one side chamber 16, which is connected to the cylinder chamber 2 via a channel 17, is provided in the cylinder wall. In the embodiment, the side chamber 16 is filled with a filling material, e.g. sponge rubber. The side chamber 16 serves to balance the volume of the piston rod 4.

[0041] In the embodiment according to FIGS. 5 to 9, the piston 3 is provided with a pin 21 on which three ring disks 8, 9, 10 are housed axially displaceable.

[0042] In contrast to the embodiment described above in which the ring disks 8, 9, 10, 11 are developed on a common hub, the ring disks 8, 9, 10 in this embodiment are developed as separate disks divided from one another.

[0043] Each ring disk 8, 9, 10 has in the area of the hub a ring projection 18, 19, 20, with which it rests against the back ring disk 9, 10 or against the piston 3. The terms forward and back are to be understood in this context as referring to the direction of movement of the piston 3 during damping. During damping the piston 3 moves forward.

[0044] A star-shaped guide 22, which rests against the inner cylinder wall, is arranged at the tip of the pin 21. For this purpose, there can be a ring gap 23 between the piston 3 and the cylinder wall. The guide 22 also serves to support the spring 7 which is arranged in this embodiment in the cylinder 1.

[0045]FIG. 5 shows the piston 3 and the ring disks 8, 9, 10 in the open and resting position.

[0046] The ring disk 8 rests against the guide 22, the ring disk 9 against the ring disk 8 and the ring disk 10 against the ring disk 9.

[0047] If the piston 3 of the damper is moved at low speed or at the beginning of the damping movement, the ring disks 8, 9, 10 at the pin 21 are displaced towards the piston 3. This situation is shown in FIG. 6.

[0048] Upon further damping movement of the piston 3, firstly the ring disk 10, as shown in FIG. 7, is bent towards the piston 3 and thus partly covers the openings 15 in the piston 3. With increasing speed or increasing damping movement, the ring disk 9, as shown in FIG. 8, is also bent, as a result of which the throughflow volume towards the piston 3 is further reduced. Finally or at high speed, the ring disk 8 also bends and thus closes the throughflow to the openings 15 in the ring disks 9, 10 located behind it and in the piston 3. At the same time as the ring disks 8, 9, 10, are bent the ring projections 18, 19, 20 are bent. This is due to the material and the thickness of the ring projections 18, 19, 20. Because the ring disks 8, 9, 10 move closer together, a better sealing is achieved. Upon the return movement of the piston 3, the gaps between the ring disks 8, 9, 10 are enlarged again and the possible throughflow volume of the damping fluid increased.

[0049] The ring disks 8, 9, 10 are made as in the previously described embodiment of a flexible material, preferably from a plastics material and again have different thicknesses and thus different rigidities.

[0050] In FIG. 10, the piston 3 is shown in the return movement. The ring disks 8, 9, 10 and the guide 22 are designed such that the ring disks 8, 9, 10 are bent towards the side facing away from the piston 3.

[0051] The openings 15 in the ring disks 8, 9, 10 are deformed during damping and during bending of the ring disks 8, 9, 10 such that they form funnel-shaped nozzles as shown in FIG. 12.

[0052] In the embodiment according to FIGS. 13 and 14, the ring disks 8, 9, 10 are again developed as separate disks which are axially displaceable at the pin 21.

[0053] Springs 24, 25, 26 are located between the ring disks 8, 9, 10 and the piston 3. The springs 24, 25, 26 are compression and coil springs and in the resting position separate the ring disks 8, 9, 10 from one another and from the piston 3.

[0054] Analogously to the different rigidities of the ring disks 8, 9, 10 in the embodiments described above, the springs 24, 25, 26 are developed with different thicknesses. Spring 26 is the weakest, spring 25 is thicker and spring 24 is the thickest spring. This is ensures that during the damping stroke of the piston 3, firstly the ring disk 10 moves towards the piston 3 and covers same. The ring disk 9 is then moved towards the ring disk 10 and finally the ring disk 8, which has no opening 15, towards the ring disk 9.

[0055] In the embodiment according to FIGS. 13 to 16, the ring disks 8, 9, 10 are inherently rigid, i.e. unbendable. At their extreme periphery, they are provided with a surrounding projecting edge 27.

[0056] When the ring disk 10, as shown in FIG. 14, rests against the face of the piston 3, it completely covers the piston 3 and the throughflow quantity of the damping fluid is limited by the two openings 15 in the ring disk 10. When the ring disk 9, as shown in FIG. 15, rests against the ring disk 10, the throughflow quantity of the damping fluid is determined by the one opening 15 in the ring disk 9. In the situation shown in FIG. 16, when the ring disk 8 rests against the ring disk 9, the throughflow through the piston 3 for the damping fluid is blocked, and the damping fluid can now only take the path via the ring gap 23 between piston 3 and the inner housing wall 13.

[0057] In the embodiment according to FIG. 17, ring disks 8, 9, 10 with ring projections 18, 19, 20 are arranged at the pin 21 in the hub area and a flat ring disk 11 which is located between the ring disks 10 and the piston 3 and which just like the ring disks 8, 9, 10 is axially displaceable at the pin 21. The ring disks 8, 9, 10 are again elastically bendable. As the ring disk 11 is flat and in the damping position rests snugly against the face of the piston, no bending occurs.

[0058] In the embodiment shown, the piston 3 has six openings 15 which are designed as bores. The ring disk 11 is provided with three openings.

[0059] In FIG. 17, the piston 3 is again shown in the resting and starting position. At the very start of the damping movement, which is shown in FIG. 18, the ring disk 9, 11 strikes the piston 3 and, as the ring disk 11 is provided with only three openings 15, the throughflow volume through the piston 3 is immediately halved. This enables good damping values to be achieved even with a thinner oil. The thinner oil brings with it the advantage that a weaker spring 7 can be used for the return of the piston 3.

[0060] As damping progresses, the elastically bendable ring disks 8, 9, 10 are bent towards each other as in the embodiments described above so that the overall cross-section of the openings 15 is progressively reduced to nil.

[0061]FIG. 22a shows a top view of the face of a piston 3, FIG. 22b a top view of the ring disk 11, FIG. 22c a top view of the ring disk 8, FIG. 22d a top view of the ring disk 9, FIG. 22e a top view of the ring disk 8 and FIG. 22f a top view of the guide 22.

[0062] As can be seen from FIG. 22b, the ring disk 11 is provided with three openings 15. The ring disk 11 is preferably held in rotation-resistance manner on the pin 21 so that the openings 15 in the ring disk 11 match openings 15 in the piston 3. If the ring disk 11 rests against the face of the piston 3, the damping fluid can now only flow through the three openings 15 in the ring disk 11, and the overall cross-section of the openings 15 is thereby halved.

[0063] Bending the ring disk 10 causes a further throttling which is continued by bending the ring disk 9. In the position shown in FIG. 21, the ring disk 8 closes the complete throughflow through the piston 3.

[0064] In the embodiment according to FIGS. 23 to 25, the piston 3 is provided with only one ring disk 8, which has no opening 15.

[0065] During the damping process, the ring disk 8 is first displaced at the pin 21 from the position shown in FIG. 23 into the position shown in FIG. 24, resting with its ring projection 18 against the face of the piston 3. The ring disk 8 is then bent, as shown in FIG. 25, as a result of which the openings 15 in the piston 3 are covered.

[0066] In the embodiment according to FIG. 26, the piston 3 is likewise provided with only one ring disk 10, however this has two openings 15. The throughflow for the damping fluid through the piston 3 is therefore never stopped completely.

[0067] In the embodiment according to FIGS. 27 and 28, a ring disk 8 is provided with an inherent tension which, in the resting position, as shown in FIG. 27, causes it to stand out from the face of the piston 3. During the damping stroke of the piston 3, the ring disk 8 is bent back so that, as shown in FIG. 28, it lies flat against the piston 3 and thus closes all the openings 15 in the piston 3. The openings 15 are not shown in FIGS. 27 and 28. 

1. Fluid damper, in particular for moving furniture parts, with a cylinder and a piston linearly displaceable therein which has at least one opening for a damping fluid provided in the cylinder, and at least one movable ring disk in the area of the opening(s), characterized in that the at least one ring disk (8, 9, 10, 11) is arranged such that it at least partially covers the opening(s) (15) of the piston (3) during the damping stroke of the piston (3).
 2. Fluid damper according to claim 1, characterized in that at least two ring disks (8, 9) are provided, at least one of the ring disks (8, 9) being provided with openings (15) for the damping fluid.
 3. Fluid damper according to claim 2, characterized in that three ring disks (8, 9, 10) are provided, two of which have openings (15) for the damping fluid.
 4. Fluid damper according to one of claims 1 to 3, characterized in that the ring disk(s) (8, 9, 10, 11) is or are arranged at the side of the piston (3) that is at the front only during the damping stroke.
 5. Fluid damper according to one of claims 1 to 4, characterized in that the piston (3) has a piston rod (4) and in that the ring disk(s) (8, 9, 10, 11) is or are arranged on the side of the piston (3) lying opposite the piston rod.
 6. Fluid damper according to one of claims 1 to 5, characterized in that the ring disk(s) (8, 9, 10, 11) is or are elastically bendable during the damping stroke.
 7. Fluid damper according to claim 6, characterized in that several ring disks (8, 9, 10, 11) are provided with different rigidities.
 8. Fluid damper according to claim 7, characterized in that the ring disks (8, 9, 10, 11) have different thicknesses (D).
 9. Fluid damper according to one of claims 1 to 8, characterized in that the ring disks (8, 9, 10, 11) are arranged such that, during the damping stroke of the piston (3), in each case one ring disk (9, 10, 11) at least partially covers the openings (15) of the ring disk (8, 9, 10, 11) lying behind.
 10. Fluid damper according to claim 9, characterized in that, during the damping stroke of the piston (3), in each case a bent ring disk (8, 9, 10, 11) at least partially covers the openings (15) of the ring disk (9, 10, 11) lying behind.
 11. Fluid damper according to one of claims 1 to 10, characterized in that the ring disks (8, 9, 10, 11) are provided from the front to the rear with an increasing number of openings (15) in the direction of movement of the piston (3) during damping.
 12. Fluid damper according to one of claims 1 to 11, characterized in that viewed in the direction of movement of piston during damping, a ring disk (8) which has no opening (15) is provided at the front at the piston (3).
 13. Fluid damper according to claim 12, characterized in that this front ring disk (8, 9, 10) is elastically bendable.
 14. Fluid damper according to one of claims 1 to 13, characterized in that all the elastically bendable ring disks (8, 9, 10, 11) are made of a rubber or plastics material.
 15. Fluid damper according to one of claims 1 to 14, characterized in that there are ring gaps (14) between the elastically bendable ring disks (8, 9, 10, 11) and the cylinder wall (13).
 16. Fluid damper according to one of claims 1 to 15, characterized in that the piston (3) is provided with a pin (21) on which the ring disks (8, 9, 10, 11) are housed axially displaceable.
 17. Fluid damper according to one of claims 1 to 16, characterized in that the ring disks (8, 9, 10) have ring projections (18, 19, 20) in the hub area.
 18. Fluid damper according to one of claims 1 to 17, characterized in that springs (24, 25, 26) are provided which, in the resting position of the piston (3), separate the ring disks (8, 9, 10) from the piston (3) and from one another.
 19. Fluid damper according to claim 18, characterized in that the springs (24, 25, 26) are of different thicknesses.
 20. Fluid damper according to claim 19, characterized in that the weakest spring (26) is arranged at the piston (3) and the thickest spring (24) behind the foremost ring disk (8).
 21. Fluid damper according to one of claims 1 to 20, characterized in that the ring disks (8, 9, 10) are provided with a peripheral ring projection (27).
 22. Fluid damper according to claim 16, characterized in that several ring disks (8, 9, 10, 11) are housed on the pin (21), a flat ring disk (11) being housed directly in front of the piston (3), which is freely displaceable on the pin, whereas the remaining ring disks (8, 9, 10) have ring projections (18, 19, 20) in the hub area and/or are separated from the adjacent disk (8, 9, 10, 11) by means of springs (24, 25, 26).
 23. Fluid damper according to one of claims 1 to 22, characterized in that the piston (2) is provided with three movable ring disks (8, 9, 10, 11) and in that the first ring disk (8) which is foremost in the direction of the damping movement of the piston (3) has no opening, the adjacent second ring disk (9) one opening (15), and the third ring disk (10) two openings (15).
 24. Fluid damper according to claim 22 or 23, characterized in that in sum the cross-sections of the openings (15) of the flat ring disk (11) are approximately half as large as the sum of the diameters of the openings (15) of the piston (3).
 25. Fluid damper according to one of claims 1 to 7, characterized in that at least one side chamber (18), with connection to the cylinder chamber (2) in which the piston (3) is guided, is provided in the cylinder wall (13). 